[Bug 27346] New: Data properties

https://www.w3.org/Bugs/Public/show_bug.cgi?id=27346

            Bug ID: 27346
           Summary: Data properties
           Product: WebAppsWG
           Version: unspecified
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: WebIDL
          Assignee: cam@mcc.id.au
          Reporter: annevk@annevk.nl
        QA Contact: public-webapps-bugzilla@w3.org
                CC: mike@w3.org, public-script-coord@w3.org

A data property of which [[Writable]] is false seems like something we could
easily expose and specifications such as https://encoding.spec.whatwg.org/
could make use of for data that is essentially static.

The main problem here could be people using it for places where a getter would
really work better to be able to lazily compute the object. Hopefully review
and implementation stages catch such mistakes.


The problem with a data property for which [[Writable]] is true seems to be (I
have not verified this):

* You cannot have type restrictions.
* C++ cannot have fast-path for using it since it has to pierce through into
JavaScript to inspect the current value each time it needs it (and then apply
some kind of coercion).

So perhaps for now we should not allow these.

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Received on Monday, 17 November 2014 14:24:06 UTC